The invention relates to medicine and means of medical engineering; it can find application in treating a number of diseases with the aid of breathing gas mixtures, including affections resulting from emergency situations.
One prior-art method for producing a gas mixture for intermittent normobaric hypoxia is known to comprise depleting atmospheric air of oxygen by compressing it in a compressor up to 0.3 to 1.5 MPa and passing the thus-compressed air through a polymer membrane made of hollow fibres, followed by feeding the resultant mixture to the patient through a-flow rate meter, a humidifier, and a mask provided with a breathing valve, and a device for carrying said method into effect, comprising a breathing bag, a mask with a breathing valve, to which mask the prepared gas mixture is fed along pipings, a compressor, a polymer membrane, a humidifier, a flow rate meter, and a gas analyzer (RU 2,004,261, A2 1994, IPC A61M 16/00).
The closest to the method proposed in the present invention is the method for forming a breathing gas mixture by mixing compressed gases fed along a piping, followed by controlled feeding of said gas mixture to the breathing mask, and an apparatus which realizes said method, comprising- a device for producing a gas mixture, having a source of compressed gas, said source communicating therewith through a gas mixture composition regulator and a flow rate meter, a breathing bag, a breathing mask with an inhalation valve and an exhalation valve, an oxygen gas analyzer, and a control unit (SU 1,793,934, A2, 1993, A61M 16/00).
However, field of application of said known methods, apparatus, and devices in medical practice is limited due to an insufficient therapeutic efficacy stemming from the fact that they use an atmospheric air (nitrogen-oxygen) mixture as the breathing mixture.
The present invention has for its principal object to extend the functional capabilities and increase the efficiency of treatment by modifying a qualitative composition of inhaled gas mixtures, as well as to reduce the consumption of gases constituting said mixtures.
The foregoing object is accomplished in a method for forming a breathing gas mixture, comprising feeding said mixture in a circulatory flow at a volume rate of flow from 3 to 120 l/min and cleaning it of carbon dioxide, moisture, and harmful microimpurities; the temperature of the gas mixture when inhaled is controlled in a range of from minus 10 to plus 130xc2x0 C.; there are also fed to said mask binary and multicomponent gas mixtures of the various qualitative and quantitative composition, said gas mixtures containing oxygen and at least one of the following gases (with a maximum 95% percent content of each gas in the mixture involved): helium, and/or argon, and/or neon, and/or krypton, and/or xenon, and/or radon, and/or nitrogen, and/or nitrous oxide, and/or sulfur hexafluoride, or a mixture thereof; the breathing mixture may be doped with medicinal agents; the carbon-dioxide content of the inhaled air may be adjusted in a range from 0.0001 to 5%, using the exhaled carbon dioxide for the purpose; inhalation resistance may be reduced by admitting an excess pressure; the carbon-dioxide absorption conditions may be improved by increasing the rate of gas mixture flow through a sorbent bed, and the carbon-dioxide content of the inhaled gas mixture may be adjusted by bifurcating the exhaled gas mixture flow into two streams one of which is admitted to pass through the sorbent bed, while the other stream bypasses the latter.
The foregoing object is also accomplished in an apparatus for forming a breathing gas mixture, comprising a device for producing a gas mixture, said device appearing as a number of containers holding compressed oxygen and also at least one of the following gases: helium, and/or argon, and/or neon, and/or krypton, and/or xenon, and/or radon, and/or nitrogen, and/or nitrous oxide, and/or sulfur hexafluoride, or a mixture thereof, said containers communicating with a breathing bag through pipings provided with stop valves, at least the compressed oxygen container being provided with a valve remote-controlled from the control unit; the apparatus is provided with a circulation circuit built up by the breathing bag, a gas flow inducer, a temperature controller, and at least one absorbent filter of carbon dioxide, moisture, and harmful microimpurities exhaled by the patient into the apparatus, all these intercommunicating through pipings; said circulation circuit communicates with an oxygen gas analyzer and is additionally provided with a carbon-dioxide gas analyzer and a temperature gauge, both of which establish, together with said oxygen analyzer, a measuring unit electrically connected to the control unit, and the mask is connected, through pipings with valves, to said circulation circuit; an inhaler may be interposed between the inhalation valve and the mask and be connected to the piping that feeds the gas mixture to the mask, said inhaler being aimed at feeding medicinal agents or moisture; the carbon-dioxide absorbent filter may be by-passed by an additional piping provided with stop valves and aimed at feeding part of a carbon dioxide-enriched gas flow directly to the breathing bag, thus by-passing said carbon-dioxide absorbent filter; an exhalation piping may be provided with a gas flow switch in order that the apparatus may operate on an open cycle; the sorbent may be re-vivifiable and be provided with a thermal reactivator; the apparatus may further comprise a device for cleaning gases of microflora, said device being cut into the gas-mixture exhalation piping; the circulation circuit may comprise a non-return valve preventing reversal of the gas flow; the apparatus may further comprise a device for determining patient""s basal metabolism against his/her breathing, and the breathing bag may be provided with a relief valve with an adjustable pressure setting.
The herein-proposed method for producing a breathing gas mixture contemplates use of rather costly gases, especially helium, whereas performing circulation jointly with regeneration of a predetermined mixture with the aid of the proposed apparatus is most economic and efficient as minimizing loss of the gases used.
Practical utilization of the present invention enables one to obtain a technical effect consisting in that use of gases having properties other than air has contributes to a high therapeutic effect, while feeding gases in a circulation flow and their regeneration allows of using the gas mixture both efficiently and economically, and the use of the invention becomes more efficient due to the fact that the temperature of the breathing mixture is controlled and inhalation of medicinal agents is provided.
Furthermore, a possibility of using a variety of gases in the breathing mixture allows of rendering medical aid to patients who sustained overcooling, this being due to extrahigh heat conductivity of helium. On the other hand, use of, e.g., nitrous oxide enables one to relieve pain in wounded patients, as well as to use the apparatus as the anesthesia apparatus in surgery.